PN45 Pressure Trace IMR4227 & 200xtp
Feb 7, 2011 17:10:09 GMT -5
Post by TGinPA on Feb 7, 2011 17:10:09 GMT -5
PN45 Pressure Trace IMR4227 and 200xtp (sabotted)
IMR 4227 had been abandoned by many because it ignited inconsistently when used in the 50 cal loads. In a a recent thread, it was suggested that this powder might more be useful in a 45 cal barrel. I thought it might be helpful to obtain some pressure numbers to help guide future tests of its efficacy. My pressure measurement setup is as described below:
Computer: Dell Inspiron Mini Notebook Gage and Module Manufacturer = RSI USB model
Trigger Sensitivity = 3, Strain Gage Voltage = 4.8 Gage Factor =2.1 PSI Correction Factor: None
Barrel Temp = 68-72 degrees F. measured at the sensor (IR). Rifle Stand: Caldwell Lead Sled
Altitude: 450 ft Chronograph: Chrony Alpha Model
Barrel Type: PacNor .45 Cal Muzzleloader Barrel OD = 1.06 in Barrel ID = .454
Breech Plug: Savage Std. (screw-in ventliner) ventliner orifice .031in. Sensor dist fm BP=.596 in.
Bullet Diam.= .448 Bullet Type = Hornady 200 gr 10 mm. XTP. Bullet weight = 200 gr. ,unknurled
Sabot: Harvester Smooth Blue
Powder:
Trace 1: IMR4227 45 gr. Primer :Fed 209
Trace 2: IMR4227 50 gr. Primer :Fed 209
Trace 3 IMR 4227 55gr. Primer:Fed 209
Trace 4: IMR 4227 55gr. Primer: Fed209 + lubed wad
Shot fm clean barrel, 1 patch Bore Shine, 1 dry patch
Using a 200gr 10mm XTP bullet in a Harvester blue sabot, I tested three different loads of IMR 4227 in the following order:
Shot 1: 45 gr., shot 2: 50 gr., shots 3 and 4: both 55gr. All pressures seemed somewhat low. I believe that Edges Quickload peak pressure estimate was about 39k psi for the 50 gr. Powder charge and I measured 10 k psi below that. Low bullet seating pressure which seemed no more than 40-50 lbs may have accounted for some of the difference. Unexpectedly, the test showed a decrement in peak pressures when increasing the powder charge from 50 to 55 gr. The only explanation I could think of for this unexpected result was that perhaps the sabot disrupted at the higher load. But the peak pressures seem low for that. Maybe others have seen this with this or other loads and will offer a better explanation. Measured barrel temperature was never above 72 degrees.
At the least, the numbers give some idea of pressure with this bullet using IMR 4227 at these levels. The loads used here seemed safe in my barrel under the conditions present when the tests were run, but may not be so in other conditions and barrels.
IMR 4227 had been abandoned by many because it ignited inconsistently when used in the 50 cal loads. In a a recent thread, it was suggested that this powder might more be useful in a 45 cal barrel. I thought it might be helpful to obtain some pressure numbers to help guide future tests of its efficacy. My pressure measurement setup is as described below:
Computer: Dell Inspiron Mini Notebook Gage and Module Manufacturer = RSI USB model
Trigger Sensitivity = 3, Strain Gage Voltage = 4.8 Gage Factor =2.1 PSI Correction Factor: None
Barrel Temp = 68-72 degrees F. measured at the sensor (IR). Rifle Stand: Caldwell Lead Sled
Altitude: 450 ft Chronograph: Chrony Alpha Model
Barrel Type: PacNor .45 Cal Muzzleloader Barrel OD = 1.06 in Barrel ID = .454
Breech Plug: Savage Std. (screw-in ventliner) ventliner orifice .031in. Sensor dist fm BP=.596 in.
Bullet Diam.= .448 Bullet Type = Hornady 200 gr 10 mm. XTP. Bullet weight = 200 gr. ,unknurled
Sabot: Harvester Smooth Blue
Powder:
Trace 1: IMR4227 45 gr. Primer :Fed 209
Trace 2: IMR4227 50 gr. Primer :Fed 209
Trace 3 IMR 4227 55gr. Primer:Fed 209
Trace 4: IMR 4227 55gr. Primer: Fed209 + lubed wad
Shot fm clean barrel, 1 patch Bore Shine, 1 dry patch
Using a 200gr 10mm XTP bullet in a Harvester blue sabot, I tested three different loads of IMR 4227 in the following order:
Shot 1: 45 gr., shot 2: 50 gr., shots 3 and 4: both 55gr. All pressures seemed somewhat low. I believe that Edges Quickload peak pressure estimate was about 39k psi for the 50 gr. Powder charge and I measured 10 k psi below that. Low bullet seating pressure which seemed no more than 40-50 lbs may have accounted for some of the difference. Unexpectedly, the test showed a decrement in peak pressures when increasing the powder charge from 50 to 55 gr. The only explanation I could think of for this unexpected result was that perhaps the sabot disrupted at the higher load. But the peak pressures seem low for that. Maybe others have seen this with this or other loads and will offer a better explanation. Measured barrel temperature was never above 72 degrees.
At the least, the numbers give some idea of pressure with this bullet using IMR 4227 at these levels. The loads used here seemed safe in my barrel under the conditions present when the tests were run, but may not be so in other conditions and barrels.